Both men and women are responsible for creating life, but often the burden of preventing pregnancy falls to women. As such, a variety of birth control options over the decades became available to women, while men have been limited to sterilization and using condoms.
Co-sponsored by the United Nations, researchers conducted a study – which was published recently in the Journal of Clinical Endocrinology and Metabolism – which proved that while this contraceptive injection being given to male study participant was successful in preventing pregnancy, it was also causing some negative side effects, including mood swings and depression.
Researchers tested the effectiveness and safety of the shot in 320 healthy men who were in monogamous relationships with female partners. Enrollment for the study began in 2008 and the research was conducted at health centers around the world. Male subjects ranged in age from 18 to 45 and previously underwent testing to make sure they had normal sperm counts before trials began.
Hormone injections trick brain into believing body has produced enough testosterone
Injections were given every eight weeks and consisted of 1,000 mg of a synthetic form of testosterone and 200 mg of norethisterone enanthate, which is practically a derivative of the female hormones progesterone and estrogen referred to as “progestin” in synthetic form, CNN reported.
Dr. Seth Cohen, a urologist at NYU Langone Medical Center who was not involved in the study, told the news network that when a man receives a shot of testosterone, “basically the brain assumes the body is getting enough,” so it shuts down its own production of the hormone and specifically “the testicle’s production of testosterone as well as the testicle’s production of sperm.”
He explained further that progestin also “drives the brain malfunction,” which also stops the testicle’s production of testosterone and sperm.
Researchers in the study used a several hormones to reduce the testosterone dose to a level they thought that, based on earlier studies, would lower fertility effectively while remaining safe.
CNN noted further:
During the ramp-up pre-efficacy stage of the study, the couples were instructed to use non-hormonal birth control methods, while the men participants received shots and provided semen samples until their sperm counts dropped to less than 1 million per milliliter in two consecutive tests. At that point, couples relied on the injections as contraception.
Throughout the course of the study, male participants gave semen samples to researchers, to ensure that sperm counts remained low. Once the injections were halted, subjects were further monitored to see if and how quickly sperm counts rose to levels considered “fertile” by the World Health Organization.
Depression, overdose and mood changes ends study early
Researchers found that the injections held sperm counts at 1 million per milliliter or less within 24 weeks for 274 study participants. The male contraceptive measure was effective for almost 96 percent of continuing users.
During the study four pregnancies which resulted in three live births occurred among the male’s partners. Doug Colvard, co-author of the study and deputy director for programs at the non-profit research center CONRAD, of Eastern Virginia Medical School – a study co-sponsor – said the babies were all normal.
But there were problems with the study as well. Serious negative effects from the injections included one case of depression and one experience of an abnormally rapid and irregular heartbeat after the shots ended. Researchers also considered one intentional overdose of acetaminophen was possibly related.
CBS added that researchers actually ended the study earlier because of mood changes and depression among some participants.